A dedicated digital subscriber line (Digital Subscriber Line, DSL) technology is a user access technology based on an ordinary telephone line. A data signal and a voice signal are separately transmitted through a same copper twisted pair, and the data signal does not pass through a telephone exchange, which reduces load of the telephone exchange; and a user may keep online with no need to dial, which belongs to a dedicated network access manner. FIG. 1 is an exemplary diagram of a copper twisted pair access manner in the prior art. As shown in FIG. 1, a modem on a user side connects to an access device on a network side by using a copper twisted pair, and performs modulation processing and demodulation processing on a data signal, so as to implement uplink transmission and downlink transmission of the data signal. Meanwhile, the modem communicates with a user equipment through a Gigabit Ethernet (Gigabit Ethernet, GE) interface or Wi-Fi, where the user equipment may be a personal computer.
There is another user access technology, that is, fiber access (Fiber-to-the-x, FTTx) technology. The FTTx technology includes fiber to the home (FTTH), fiber to the premise (FTTP), FTTC fiber to the curb or the neighborhood, FTTN fiber to the node, FTTO fiber to the office, and FTTSA fiber to the service area (FTTx, x=H for home, P for premises, C for curb and N for node or neighborhood, O for office, SA for service area). The FTTx technology mainly uses a passive optical network (Passive Optical Network, PON) access technology to provide access for a user. FIG. 2 is an exemplary diagram of a PON access manner in the prior art. As shown in FIG. 2, a modem of an optical signal on a user side connects to an access device on a network side by using an optical fiber of a PON, performs modulation processing and demodulation processing on a data signal, and provides the data signal for a user. Meanwhile, the modem of the optical signal communicates with a user equipment through an RJ 45 interface or Wi-Fi.
For the foregoing two user access manners, bandwidth in a copper twisted pair access manner is less than bandwidth in an optical fiber access manner. The copper twisted pair access manner is gradually replaced with the optical fiber access manner, which results in discarding of many copper twisted pairs. In addition, in the optical fiber access manner, a PON is a passive network; therefore, power of a modem of an optical signal needs to be supplied by an external power supply.
However, after the external power supply of the modem is powered off, the modem cannot provide a service for a user because of the power-off, causing that a user side of the modem cannot use a data service and a voice service.
Currently, a copper twisted pair supplies power to a user telephone in a wired manner, where the telephone needs to be connected to a line telephone port by using the copper twisted pair, so as to obtain power. However, a limitation on a location of a telephone line port in a home exists, and a telephone can obtain power only if the telephone supports a connection with the telephone line port; therefore, the telephone cannot conveniently obtain the power.